Selective conversion of acrylonitrile into 1,4-dicyano-1-butene catalyzed by plymer-bound alkyl diarylphosphinites

ABSTRACT

Selective conversion of acrylonitrile into 1,4-dicyano-1-butene by contacting a liquid phase comprising acrylonitrile with an effective amount of a polymer-bound alkyl diarylphosphinite catalyst having the formula I: ##STR1## wherein the trivalent phosphorus is substituted by one alkoxy group and one aryl group and wherein the third bond of phosphorus is a P--C bond to a pendant aryl group of the polymer matrix, such as polystyrene cross-linked with divinylbenzene is disclosed. Treatment of the liquid phase, prior to contacting same with the polymer-bound catalyst, with a drying agent comprising a polymer-bound dialkyl arylphosphonite and regeneration of the drying agent are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division, of application Ser. No. 438,687, filedNov. 3, 1982 now U.S. Pat. No. 4,574,060.

BACKGROUND OF THE INVENTION

This invention relates to the preparation of 1,4-dicyano-1-butene bycontacting a liquid phase comprising acrylonitrile with an effectiveamount of a polymer-bound alkyl diarylphosphinite catalyst having theformula I: ##STR2## wherein the trivalent phosphorus is substituted byone alkoxy group and one aryl group and wherein the third bond ofphosphorus is a P--C bond to a pendant aryl group of the polymer matrix.

The dimerization of acrylonitrile to 1,4-dicyano-1-butene has been muchinvestigated as a route to adiponitrile which is hydrogenated tohexamethylene diamine, the nylon 6,6 monomer.

A process for the dimerization of acrylonitrile in the presence ofphosphines (PR₃) and phosphites (P(OR)₃) to give a 2:1 mixture of2,4-dicyano-1-butene and cis- and trans-1,4-dicyano-1-butenes isdisclosed in C.A., Vol. 62 (1965), 14508e (D. W. Henberg, et al.).

Tetrahedron Letters (1966) No. 51, pp 6347-51, (W. H. Dietsche)discloses that alkyl diarylphosphinites having the formula Ar₂ POR inthe presence of t-butanol or aqueous acetic acid effects dimerization ofacrylonitrile to 2,4-dicyano-1-butene (2-methyleneglutaronitrile) and1,4-dicyano-1-butene.

The dimerization of acrylonitrile (ACN) in the presence of varioustervalent oxygen-containing phosphorus (III) catalyst compositions and amixture of a hydrocarbon such as toluene and a proton-donating solventsuch as 2-propanol has been disclosed in a series of U.S. patentsgranted to personnel of Imperial Chemical Industries (ICI).

U.S. Pat. No. 4,102,915 (Jennings et al.) discloses that a process fordimerization of ACN to substantially linear C₆ dimers using homogeneous,i.e., soluble organic phosphinites or phosphonites as catalysts, iseffected in the presence of a proton-donating solvent and optionally ahydrocarbon co-solvent, wherein ACN and solvents are dry and free ofoxygen and wherein at least one of the solvents has a boiling pointhigher than ACN and is capable of phase separation with respect todimeric products, to enable unreacted ACN to be removed by distillationand the solvent(s) and dimeric products to be separated.

U.S. Pat. No. 4,316,857 (Gilbert) discloses a soluble phosphonite orphosphinite catalyzed ACN dimerization process that uses as a solvent amixture of a proton-donating organic solvent, an aromatic hydrocarbonsolvent and an aliphatic hydrocarbon solvent in a specified ratio so asto facilitate product isolation such as by phase separation or liquidextraction.

U.S. Pat. No. 4,238,422 (Cozens et al.) discloses soluble arylphosphinites and phosphonites useful as ACN dimerization catalystswherein the aryl groups are substituted by at least oneelectron-donating group.

U.S. Pat. Nos. 4,138,428 and 4,190,616 (Jennings et al.,) disclose ACNdimerization process and soluble organic phosphinite or phosphonitecatalysts having at least one aryl group substituted byelectron-donating substituents.

U.S. Pat. No. 4,263,224 (Jennings et al.) discloses ACN dimerizationprocess wherein an aryl phosphonite or phosphinite is added as alow-cost scavenging reagent to a mixture of ACN and organic solvent toremove therefrom residual traces of water or other catalyst deactivatingimpurities before contacting said reaction mixture with a more expensivesoluble aryl phosphinite or aryl phosphonite dimerization catalyst.

U.S. Pat. No. 4,126,632 (Hogan et al.) discloses a process for thedimerization of ACN to straight chain 1,4-dicyanobutenes by contactingACN with organic phosphinite or phosphonite catalyst having the formulaR₁ R₂ R₃ P or (R₁ R₂ P)₂ R₄ wherein at least one of the R groups R₂ orR₃ is alkoxy or cycloalkoxy and R₄ is alkylene or alkylenedioxy in thepresence of an inert proton-donating solvent and optionally an inerthydrocarbon co-solvent. While this patent also provides examples ofsoluble phosphinites and phosphonite wherein groups R₁ to R₄ are alkyl,aryl, cycloalkyl, polyalkylene, etc., the patent also discloses withoutexamples that groups R₁ to R₄ may also be part of a polymeric backbone,for example, polystyrene or polyvinylalcohol or be linked to aninorganic support, for example, silica or alumina, so as to form aheterogeneous catalyst.

U.S. Pat. Nos. 4,059,542 and 4,089,890 (Jennings, et al.) disclose thatsilica- or alumina-bound phosphinites or phosphonites as heterogeneous,i.e., insoluble catalyst compositions may only be used for the gas-phasedimerization of acrylonitrile at temperatures above 150° C. When thebest phosphinite-bound to silica catalyst disclosed in U.S. Pat. Nos.4,059,542 and 4,089,890 was employed for dimerization of ACN in the gasphase at 170°-190° C., only low conversions (7-20%) of ACN into aneconomically unattractive 3:1 (maximum value) mixture of straight andbranched chain dimers and an unspecified amount of oligomers wereobserved.

The processes using soluble catalysts disclosed in these ICI patentsproduce 1,4-dicyanobutene, the desired linear dimer, at moderateconversions, in high selectivity with lesser amounts of the brancheddimer, methyleneglutaronitrile and oligomers. However, the ACNdimerization processes employing homogeneous, i.e., soluble alkyldiarylphosphinites substituted by electron-donating groups have thefollowing disadvantages. At the end of each ACN dimerization run, beforedistillation of the desired dimeric products, the soluble phosphinitecatalyst must either be removed by complicated extraction procedures ordecomposed with water. The extraction procedures inherently result inappreciable losses of the soluble phosphinite catalysts for two reasons.Firstly, the differences in the solubility of the soluble phosphinitecatalyst in the solvents are not infinite, and thus, several extractionsof the catalyst are required. Secondly, extraction enhances the chancesfor contamination of the solvents, unreacted ACN and catalyst withmoisture and oxygen, impurities which deactivate the catalyst.Decomposition of the soluble phosphinite catalyst by the addition ofwater substantially increases catalyst consumption and contaminates thereaction solvents (isopropanol and toluene) and unreacted ACN with waterand/or oxygen. Thus, after extraction and decomposition procedures, thereaction solvents and unreacted ACN must be degassed and redried beforethe recycle of same. In the case of isopropanol and ACN, degassing andredrying are very costly and time consuming steps.

One way in which the workup of the dimerization reaction could begreatly simplified, while simultaneously conserving the expensivecatalyst, would be to support the catalyst on a polymer matrix. C. U.Pitman, et al. (CHEMTECH, September 1973, pp 560-566) Pitman, et al.(CHEMTECH, September 1973, pp 560-566) disclose that soluble catalysts,e.g., transition metal catalyst, may be bound to polymer backbones. Seealso Paper No. 29 by W. O. Haag, et al., in "Proc. 5th InternationalCongress on Catalysis", Vol.1, pp 465-472 (1973) and an article by D. D.Whitehurst in CHEMTECH, January, 1980, pp 44-49.

During the course of development of the present invention, phosphinitesbound to organic polymer matrices via P--O--C bonds were prepared andwere found to be impractical and inactive catalysts for ACNdimerization. Similarly, phosphinites bound via P--O--M bonds toinorganic matrices (M), as disclosed in U.S. Pat. Nos. 4,089,890 and4,059,542 (ICI), possess a low activity and low selectivity and may beused only for gas phase ACN dimerizations. Although the above-identifiedICI U.S. patents mention the use of polystyrene-bound phosphinites, noworking example of the use and/or preparation of same is given in theabove-identified ICI U.S. patents or in other published literature ofwhich we are aware.

Accordingly, it is an object of the present invention to provide an ACNdimerization process that employs a heterogeneous catalyst that avoidsthe complicated workup and product isolation procedures of prior artwhile preserving the integrity of the catalyst.

These and other objects and advantages of the present invention willbecome obvious in view of the following description.

SUMMARY OF THE INVENTION

According to an object of the present invention, we provide a processfor conversion of acrylonitrile into 1,4-dicyano-1-butene whichcomprises contacting a liquid phase comprising acrylonitrile with aneffective amount of a polymer-bound alkyl diarylphosphinite catalysthaving the formula I: ##STR3## wherein the trivalent phosphorus issubstituted by one alkoxy group and one aryl group and wherein the thirdbond of phosphorus is a P--C bond to a pendant aryl group of the polymermatrix for a time sufficient to effect conversion to a stream containing1,4-dicyano-1-butene.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1b are ³¹ P NMR Spectra of preferred embodiments of apolymer-bound phosphinite catalyst of the present invention.

FIG. 2 schematically illustrates operation of the polymer-boundphosphinite catalyst of the present invention in a flow reactor.

FIG. 3 graphically illustrates the variation in the percent conversionof ACN vs reaction time for the polymer-bound phosphinite catalyst ofthe present invention operated as shown in FIG. 2.

FIG. 4 schematically illustrates one synthetic pathway for preparationof a polymer-bound alkyl diarylphosphinite catalyst of the presentinvention.

FIG. 5 schematically illustrates another synthetic pathway forpreparation of a polymer-bound alkyl diarylphosphinite catalyst of thepresent invention.

FIG. 6 schematiclly illustrates the reaction of a polymer-bound dialkylarylphosphonite with water to form a product that does not react withACN.

FIG. 7 schematically illustrates the reaction of polymer-bound dialkylphosphonite with oxygen to form catalycally inactive phosphorus V.

FIG. 8 schematically illustrates a preferred method of preparation ofthe polymer-bound dialkyl phosphonite of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a process for dimerization ofacrylonitrile that may be operated batchwise or continuously with highselectivity and high percent conversion by contacting a liquid phasecomprising acrylonitrile, at least one inert solvent, and aproton-donating solvent with a polymer-bound alkyl diarylphosphinitecatalyst having formula I, positioned in a fixed bed or in a flowreactor, for a time sufficient to effect conversion of ACN to a streamcontaining 1,4-dicyano-1-butene. Thus, the dimerization process usingthe polymer-bound catalyst composition of the present invention affordsbatchwise or continuous operation, facile product separation andrecovering of same from the reaction medium and recycling of unreactedacrylonitrile and inert proton-donating solvents while maintaining highselectivity to the preferred linear dimer, 1,4-dicyano-1-butene at ahigh conversion of ACN. Further, the immobilization of the phosphinitecatalyst on a polymer matrix eliminates the need for complicated workupprocedures of the prior art and minimizes degradation of expensiveactive catalysts by exposure of same to water and air.

In batchwise operation, the polymer-bound phosphinite catalyst isseparated by a simple filtration; in continuous operation, no separationis necessary because the effluent from the flow reactor is free ofcatalyst. In either case, the converted acrylonitrile comprising linearand branched chain dimers and oligomers are conveniently and easilyseparated from the unreacted acrylonitrile, at least one inerthydrocarbon and proton-donating solvent by a simple distillation. Thecondensed volatile components--unreacted acrylonitrile, at least oneinert hydrocarbon solvent and a proton-donating solvent--can be recycledto a batch or continuous reactor without any further purificationbecause contamination of the condensed volatile components by water oroxygen has been practically eliminated.

In a preferred embodiment of the present invention, dimerization ofacrylonitrile was effected continuously over 184 hours using a flowreactor packed with a preferred embodiment of the polymer-bound catalysthaving formula I wherein R=ethyl or isopropyl and Ar'=p-CH₃ OC₆ H₄ - ,i.e., with ○p C₆ H₄ -P(p-CH₃ OC₆ H₄ -)O-C₂ H₅ or ○p -C₆ H₄ -P(p-CH₃ OC₆H₄ -)O-i-C₃ H₇. The percent conversion slowly declined from 63%initially to 40% at 184 hours. The percent selectivity to linear andbranched dimers was 90-91% (92% linear, 8% branched).

In contradistinction thereto, trimethylsilyldibutylphosphinite, asoluble phosphinite having a P--O--Si bond and serving as a modelcompound for the phosphinites bound to silica such as disclosed in U.S.Pat. Nos. 4,059,542 and 4,089,890, was prepared (See Example 18), andwas tested as an ACN dimerization catalyst (See Example 19) but wasfound completely inactive and was, in a relatively short time (3 hrs) inthe ACN dimerization medium, converted into an catalytically inactivephosphorus (V) species. Partially phosphinited derivatives of polyvinylalcohol and of various hydroxylcontaining polymers were prepared andshowed little or no activity as ACN dimerization catalyst, in agreementwith the results of other studies conducted with 1,2- and 1,3-diols,which are not reported in the experimental section herein below. (SeeComparative Example 28 and Table V). Fully phosphinited derivatives ofhydroxylcontaining polymers required addition of proton donors, e.g.,isopropanol or neopentyl alcohol to the ACN dimerization medium. Thepresence of such proton donors caused solvolysis of the polymer-boundphosphinites and the formation of soluble monomeric phosphinites. SeeTable V for a summary of these results.

Phosphinite bound to polyvinyl alcohol (PVA), PVA cross-linked with TDIand similar OH-containing polymers such as4-(2-hydroxypropyl)polystyrene and "TOYOPEARL", a trade name for a PVAcross-linked copolymer containing aliphatic hydroxyl and non-hydroxyloxygen moities, were found to be impractical or ineffective catalystsfor ACN dimerization.

In another preferred embodiment of the present invention, the liquidphase comprising acrylonitrile, at least one inert solvent and aproton-donating solvent and containing less than 30 ppm, preferably lessthan 15 ppm water, is contacted prior to contact with the polymer-boundphosphinite catalyst, with a recyclable polymer-bound dialkylarylphosphonite which lowers the water content to 5 ppm or less. Thepolymer-bound phosphonite is conveniently contained in a fixed bed,i.e., column such as illustrated in FIG. 2, and may be recycled, i.e.,reconverted to phosphonite by scheme illustrated in FIG. 6.

By the term "% conversion", as used herein, is meant the % by weight ofacrylonitrile (ACN) that is converted to total linear/branched dimeric,oligomeric and polymeric products.

By the term "% selectivity", as used herein, is meant the % by moles ofacrylonitrile converted into linear dimers, i.e., cis- andtrans-1,4-dicyano-1-butene (DCB-1). Thus, % selectivity is defined astwice the number of moles of DCB-1 divided by moles of reactedacrylonitrile multiplied by 100%.

The liquid phase comprising acrylonitrile that is contacted with thepolymer-bound alkyl diarylphosphinite further comprises at least oneinert solvent and a proton-donating compound. The concentration (% byvolume) of acrylonitrile in the liquid phase is not critical and isconveniently adjusted between about 5% and 50% to control the rate ofreaction. Concentrations of acrylonitrile above about 50% in liquidphase lead to oligomer and polymer formation and should be avoided. Whenthe concentration of acrylonitrile is below about 5% in liquid phase,the reaction rate is too low to be practical.

Inert solvents are those compounds which do not react or interfere withthe process or catalyst or reactants of the present invention. The inertsolvents found useful in the present invention are liquid, nonhydroxylicaromatic hydrocarbon solvents, including hydrocarbons such as benzene,xylenes, toluene, and polyalkylbenzenes. Toluene is the preferred inertsolvent solely for economic reasons.

Mixtures of liquid aromatic hydrocarbons and different amounts of liquidaliphatic hydrocarbons may be used without interfering with the processof the present invention so long as the liquid phase remainshomogeneous. Thus, aliphatic or alicyclic hydrocarbons such as petroleumether or cyclohexane may be used with sufficient amounts of aromatichydrocarbon(s), preferably toluene, to insure the solubility of theproton-donating solvents. Solvents such as ethers and nitriles may alsobe used. However, the selectivity to the desired linear dimer isdecreased when the liquid phase contains polar solvents, and use of suchsolvents is to be avoided.

Proton-donating solvents such as aliphatic or cyclic alcohols are addedto facilitate the selectivity of the dimerization process of the presentinvention. Proton-donating solvents of higher acidity than alcohols suchas organic carboxylic or sulfonic acids, as well as thiols and phenols,interfere with the catalyst and must be avoided.

Secondary aliphatic groups having 3-10 carbons and cyclic secondaryalcohols having 5 to 10 carbon atoms are preferred. Primary alcohols arefound to effect dimerization of ACN, but the % selectivity is lowercompared to the process employing secondary alcohols. Use of primaryalcohols is less preferred. Tertiary alcohols interact with thepolymer-bound phosphinite catalyst to form t-alkyl phosphinites whicheliminate olefins leaving behind catalytically inactive secondaryphosphine oxides. Thus, the use of tertiary alcohols is to be avoided.

Since a fixed bed or flow system, preferably a flow system, is employed,only the ratio of proton-donating solvent, preferably isopropanol:inertsolvent, preferably toluene:acrylonitrile can be specified. The ratio(volume) of proton-donating solvent to inert solvent to acrylonitrile inthe liquid phase is about 0.2-10:10-0:1-7.5. In the preferred embodimentof the present invention, the ratio (volume) of isopropanol to tolueneto acrylonitrile is about 1:10:3. A portion of toluene may beconveniently replaced by cyclohexane and hexamethylbenzene (internalstandards).

The contact time is sufficient to convert about 5-95%, preferably about30-80% of the acrylonitrile, into the desired dimeric product. Contacttimes may conveniently be from about 10 minutes to about several hours.

The presence of water and oxygen interferes with the process or catalystof the present invention and must be avoided. Thus, acrylonitrile, theinert and proton-donating solvents and reactor must be rigorously driedbefore use. The contacting of ACN with the catalyst of the presentinvention is performed under substantially anhydrous conditions, i.e.,the concentration of water in liquid phase is preferably maintained lessthan about 30 ppm, and more preferably less than about 15 ppm, and mostpreferably less than 5 ppm. Conventional drying agents, such as CaH₂, 3Aor 4A molecular sieves, and polymer-bound dialkyl arylphosphoniteshaving the formula II, ○p -C₆ H₄ -P(OR)₂, may be employed to dry theliquid phase before the start of the reaction to a value less than 5ppm. The dimerization process of the present invention should beoperated under a dry inert atmosphere, e.g., nitrogen gas, to avoidcontamination by oxygen, water vapor, etc. during the operation of theprocess of the present invention. Stabilizers normally present inacrylonitrile such as hydroquinones or phenol-type compounds are to beremoved before contacting with the catalyst in the process of thepresent invention. In addition, scavenging agents, such as arylphosphonites that are disclosed in U.S. Pat. No. 4,263,224, may beconveniently added to liquid phase reservoirs prior to contacting samewith polymer-bound alkyl diarylphosphinite catalyst of the presentinvention. Concentrations of less than one % by volume in the liquidphase of the scavenger agents are normally sufficient to removechemicals such as H₂ O that would adversely affect the polymer-boundcatalyst of the present invention. In a preferred embodiment of thepresent invention, polymer-bound dialkyl arylphosphonites having theformula II, ○p -C₆ H₄ -P(OR)₂ wherein R is an aliphatic group of 1 to 10carbons or cyclic secondary group of 5 to 10 carbons, preferably asecondary aliphatic group such as isopropyl, are used to lower the watercontent of the liquid phase that contains acrylonitrile, inert solvent,and proton-donating solvent, and that has been subjected to conventionaldrying by reagents such as CaH₂ and molecular sieves, to a value of lessthan about 15 ppm, preferably about 5 ppm or lower, i.e., 2-3 ppm. Thepreparation of the polymer-bound dialkyl arylphosphonites is shownschematically in FIG. 8. See Example 13 hereinbelow. Levels of water inexcess of 50 ppm in the liquid phase may be tolerated. However, lowerselectivities and deactivation of large amounts of catalyst are to beexpected.

It is a special feature of the process of the present invention that thedrying agent comprising polymer-bound dialkyl phosphonite reacts withwater to form a polymer-bound alkyl phosphinate having the formula ○p-C₆ H₄ -P═O(OR)(H) that does not react with ACN but that may beconveniently reconverted into polymer-bound dialkyl arylphosphonite by asequence of steps outlined in FIG. 6. It is another special feature ofthe process of the present invention that the sequence of steps outlinedin FIG. 6 may be performed without removing same from the container usedto dry the ACN dimerization reaction medium The polymer-boundphosphinate having the formula ○p -C₆ H₄ -P═O(OR)(H) may conveniently betreated with a reagent such as PX₃, COX₂, wherein X is halogen,preferably PCl₃, for a time sufficient to produce a polymer-bound alkylarylphosphonous dichloride having the formula ○p -C₆ H₄ -P(Cl)₂. Thepolymer-bound phosphonus dichloride is then treated with a primary orsecondary alcohol in the presence of a base, such as pyridine, for atime sufficient to produce a polymer-bound dialkyl arylphosphonite. Thepreferred alkanol is isopropanol. The preferred polymer is polystyrenecross-linked with at least about 1 to 40 weight percent divinylbenzeneand having the form of micro- or macroreticular beads or clusters ofbeads.

The reaction temperature for ACN dimerizations of the present inventionis commonly in the range of about 0° C. to 100° C. Temperatures in therange of 50° C., to about 75° C. are preferred. A temperature of about60° C. is more preferred.

Reaction pressure is not critical and may be sub- or super-atmosphericas well as atmospheric. When the polymer-bound catalyst operates in aflow reactor, at temperatures above 50° C., super-atmospheric pressuresare commonly in the range of 1-5 atm, and preferably, about 1.5-3 atm.

The polymer-bound catalyst of the present reaction comprises apolymer-bound alkyl diarylphosphinite having the formula I, ○p -C₆ H₄-P(Ar')OR wherein the trivalent phosphorus is substituted by one alkoxygroup and one aryl group and wherein the third bond of phosphorus is aP--C bond to a pendant aryl group of the polymer matrix. Among thepolymers of the polymer-bound catalyst found useful in the presentinvention are polystyrene and polystyrene cross-linked with about 1 to40 percent by weight of divinylbenzene and in the form of micro- ormacroreticular beads or clusters of beads. Preferably, the polymer ofpolymer-bound catalyst comprises polystyrene cross-linked with about 1percent of divinylbenzene.

By the term "effective amount of polymer-bound catalyst", as usedherein, is meant that at least 1% of the pendant aryl groups of formulaI is substituted with phosphorus in the form of phosphinite.Conveniently, at least about 5 to about 100% of the pendant aromaticrings bound to polymer backbone are substituted by phosphorus. In thepreferred mode of preparation of polymer-bound catalyst of the presentinvention, at least about 25-100%, preferably 80% or more of thephosphorus bound to the aromatic rings were in the form of phosphinite.

The aromatic ring (Ar') bound only to phosphorus in the polymer-boundalkyl diarylphosphinite has the formula: ##STR4## where at least one ofthe R_(a-e) groups is an heteroatom-containing electron-donating groupselected from the group consisting of --OR³ and --N(R⁴, R⁵) wherein R³,R⁴ and R⁵ are independently straight or branched chain alkyl groupshaving 1 to 10 carbons or cycloalkyl groups having 5 to 10 carbons orwherein R_(a), R_(b), R_(c), R_(d) and R_(e) are independently selectedfrom the group consisting of said heteroatom-containingelectron-donating groups, hydrogen, straight and branched chain alkylgroups having 1 to 10 carbons and cycloalkyl groups having 5 to 10carbons or wherein two of said R_(a-e) groups form part of a fusedalicyclic system and the remainder of said R_(a-e) groups areindependently said heteroatom-containing electron-donating groups orhydrogen or a straight or branched chain alkyl groups of 1 to 10 carbonsor cycloalkyl groups of 5 to 10 carbons. Aromatic rings containing atleast one heteroatom-containing electron-donating groups or three alkylgroups are preferred. Aromatic rings containing only H are lesspreferred.

Among the heteroatom-containing electron-donating groups found useful inthe catalyst of the present invention are alkoxy (OR³), N,N-dialkylamino--N(R⁴, R⁵) wherein the alkyl groups R³, R⁴, R⁵ are straight or branchedchain aliphatic groups of 1 to 10 carbons or cycloalkyl groups of 5 to10 carbons. Preferred heteroatom-containing electron-donating groups areCH₃ O--, C₂ H₅ O--, i--C₃ H₇ O--, (CH₃)₂ N--, (C₂ H₅)₂ N--, and (n--C₃H₇)₂ N--.

Among the aromatic groups attached only to phosphorus that are useful inpolymer-bound alkyl diarylphosphinite catalyst of the present inventionare p-alkoxylphenyl, p-N,N-dialkylaminophenyl, 2,3,4,5-tetraalkylphenyl;3,4,5-, 2,3,5-,2,4,5- and 2,3,4-trialkylphenyl wherein alkyl has one toten carbons and is preferably methyl.

The polymer-bound alkyl diarylphosphinite catalysts of the presentinvention contain at least 1% of the pendant aromatic groups of thepolymer matrix, bound to phosphorus and substantially free of C═O groupssuch as e.g., aldehydes, ketones, esters and amides, or --OH, NHR or--NH₂ or SH that may react with phosphinite phosphorus or otherwiseinterfere with acitvity of the phosphinite as a selective acrylonitriledimerization catalyst. Preferred polymer-bound catalysts of the presentinvention include ○p -C₆ H₄ -P(p-CH₃ OC₆ H₄ -)OR, ○p -C₆ H₄ -P[(CH₃)₃ C₆H₂ -]OR; wherein ○p -C₆ H₄ - is derived from a polymer which comprisespolystyrene matrix and preferably, which consists essentially ofpolystyrene cross-linked with at least about 1 weight % ofdivinylbenzene and more preferably polystyrene cross-linked with atleast about 1-40 weight % of divinylbenzene and in the form of micro- ormacro-reticular beads or clusters; and wherein R is selected from thegroup consisting of straight and branched chain aliphatic groups of oneto ten carbons and cyclic groups having five to ten carbon atoms.Preferred R groups are cyclohexyl, methyl, ethyl and groups havingformula R¹ R² C(H)-- wherein R¹ and R² are independently selected fromhydrogen and straight and branched chain alkyl groups having 1 to 9carbon atoms such as isopropyl.

Synthetic pathways for the preparation of the polymer-bound alkyldiarylphosphinite catalysts of the present invention are schematicallyillustrated in FIGS. 4 and 5. See also Examples 7 and 15 hereinbelow.

GENERAL EXPERIMENTAL

Infrared spectra, as either neat films or KBr pellets, were recorded ona Perkin-Elmer 283 Spectrophotometer. Proton, ¹³ C and ³¹ P NMR wererecorded on Varian T-60, FT-80A, and XL-200 instruments. Phosphoruschemical shifts are reported relative to external 85% phosphoric acid.Gas chromatographic analyses were performed on a Hewlett Packard 5710using a 3'×1/8" Porapak P column and a Hewlett Packard 3352B computer tomonitor the retention times and peak areas.

All dimerization runs and the preparation of the polymer-bound catalystswere carried out with the careful exclusion of oxygen and moisture.Transfer of moisture-sensitive solids was carried out in a VacuumAtmospheres Dry Box. Volatile liquids were transferred on a vacuum line,while the nonvolatile, soluble catalysts were transferred via syringe ina stream of argon.

Materials

All solvents were reagent grade. Toluene and cyclohexane were storedover sodium-potassium alloy under vacuum. Tetrahydrofuran (THF) wasstirred with lithium aluminum hydride, then distilled into a solventreservoir containing sodium-potassium alloy and anthracene. The THF wasdistilled from the solution of the blue radical anion as needed.Isopropanol, tert-butyl alcohol and acrylonitrile were refluxed overcalcium hydride (-40 mesh) for at least three hours, then distilled ontoflame-dried 4A molecular sieves for storage. Neopentyl alcohol wassublimed onto flamed-dried 4A molecular sieves. After standingovernight, these reagents were sampled for water content (Karl Fisher)and found to contain <30 ppm of water. Samples were taken periodicallyto assure that the water content remained low, i.e., less than 50 ppm.Pyridine was also dried over calcium hydride and distilled ontomolecular sieves.

"TOYOPEARL® 55", the trade name for a polyvinyl alcohol cross-linkedcopolymer containing aliphatic hydroxy and non-hydroxy oxygen moieties,was obtained in the form of beads as a water slurry in superfine (20-30μm) and coarse (50-100 μm) grades from MCB, and was washed repeatedlywith water and with acetone, then dried in vacuo at 100° C. for at least24 hrs. Polyvinyl alcohol (88% hydrolyzed, avg MW 10,000) was obtainedfrom Aldrich. Ethylene vinyl alcohol copolymer (40/60) type F waspurchased from Kuraray Co., Ltd. Polyvinyl alcohol cross-linked withterephthalaldehyde and with tolylene diisocyanate were prepared asdescribed by G. Manecke et al., in Makromolekulare Chem., 117, 725(1976) and by S. Nozakura et al. in J. Polymer Sci., A, 10, 2767 (1972).

EXAMPLE 1 Preparation of Di-p-tolylphosphinites

Ethyl and isopropyl di-p-tolylphosphinites were prepared following theprocedure of Coezens, et al., as disclosed in U.S. Pat. No. 4,238,422 atCol. 8, lines 19-59, by the reaction of ethyl or isopropylphosphonodichloridite with p-tolylmagnesium bromide in THF. Aftertreatment with pyridine to precipitate the magnesium halide complex, theproduct was purified by Kugelrohr distillation at 120°-125° C. (0.1mmHg). Ethyl di-p-tolylphosphinite was also prepared fromdi-p-tolylphosphinous chloride by the procedure described in thefollowing entry. IR (neat) 1600, 1498, 1385, 1090, 1045, 817, 520 cm⁻¹ ;¹ H NMR (CDCl₃) δ7.6-7.0 (m, 8H), 3.9 (m, 2H), 2.32 (s, 6H), 1.28 (t,3H).

EXAMPLE 2 Preparation of Ethyl Diphenylphosphinite

A solution of diphenylphosphinous chloride (135 mmol) in dry ether (120mL) was treated dropwise at 5° C. with a solution of ethanol (200 mmol)and pyridine (134 mmol) in ether (120 mL). After addition was complete,the mixture was warmed to room temperature, filtered under argon, andthe solid hydrochloride washed with ether. Evaporation of the solventgave an oil which was purified by Kugelrohr distillation at 95° C. (0.1mmHg). Yield: 119 mmol (88%); ¹ H NMR (CDCl₃) δ7.6-7.2 (m, 10H), 3.95(doublet of quartets, J_(H-H) =7 Hz, J_(P-H) =10 Hz, 2H), 1.30 (t, J=7Hz, 3H).

EXAMPLE 3 p-Anisylphosphonous Dichloride and Diisopropylp-Anisylphosphonite

The phosphonous dichloride was prepared by the stannouschloride-catalyzed Friedal-Crafts reaction of phosphorus trichloride(three-fold excess) and anisole following the procedure of Miles andco-workers (J. Org. Chem., 1975, 40, 343). IR (neat) 1590, 1500, 1295,1255, 1180, 1095, 1030, 830 cm⁻¹ ; ¹ H NMR (CDCl₃) 8.0-7.6 (broad t,2H), 7.1-6.8 (broad d, 2H), 3.83 (s, 3H). The dichloride (26 mmol) wastreated in dry ether with isopropanol (62 mmol) and dimethylaniline (48mmol) at 0° C. Workup and Kugelrohr distillation at 105°-110° C. (0.05mmHg) afforded a 53% yield of the phosphonite. IR (neat 1590, 1498,1245, 1100, 955, 860, 750 cm⁻¹ ; ¹ H NMR (CDCl3) δ7.7-7.4 (m 2 H),7.1-6.8 (m, 2H), 4.3 (m, 2H), 3.78 (s, 3H), 1.25 (d, J=6 Hz, 6H), 1.20(d, J=6 Hz, 6H). The corresponding diethyl ester was prepared in 85%yield using this procedure, but with pyridine as the base instead ofdimethylaniline.

EXAMPLE 4 Ethyl p-Anisylphosphonochloridite

This and other phosphonochloridous esters were best prepared by theprocedure of Steininger (Chem. Ber., 1962, 95, 2993) for thecomproportionation of the corresponding phosphonous dichloride andphosphonite. Thus, a solution of diethyl p-anisylphosphonite (7.5 g, 36mmol) in dry ether (20 mL) was added to a solution ofp-anisylphosphonous dichloride (8.2 g, 36 mmol) in ether (75 mL) at 5°C. The solution was warmed to room temperature and stirred two hours,then concentrated and distilled (Kugelrohr) at 105°-110° C. (0.1 mmHg).Yield: 9.4 g (60%); IR (neat) 1595, 1500, 1255, 1095, 1025, 930, 824cm⁻¹ ; ¹ H NMR (CDCl₃) δ7.9-7.5 (m, 2H), 8.1-7.8 (m, 2H), 4.0 (m, 2H),3.82, (s, 3H), 1.30 (t, J=7 Hz, 3H); ³¹ P NMR (CDCl₃) δ177.2 (ca. 90%).

EXAMPLE 5 Ethyl Phenylphosphinate

A solution of phenylphosphonous dichloride (66 g, 0.37 mol) in dry ether(100 mL) was treated dropwise with a solution of ethanol (21.6 mL, 0.37mol) and pyridine (29.6 mL, 0.37 mol) in ether (200 mL) at roomtemperature under argon. After stirring for one hour, a mixture of water(6.6 mL, 0.37 mol) and pyridine (29.6 mL) was added slowly. The reactionmixture was filtered, washed with ether, and the ether evaporated togive an oil. The oil was distilled in the Kugelrohr and then through ashort Vigreux column at 95°-98° C. (0.05 mmHg); lit. (T. L. Emmick etal., J. Am. Chem. Soc., 1968, 90, 3459) 102°-103° C. (0.2 mmHg). Yield44.3 g (70%). ¹ H NMR (CDCl₃)δ7.57 (d, J=569 Hz, 1H), 8.0-7.4 (m, 5H),4.13 (2 q, J_(H-H) =7 Hz, J_(P-H) =14 Hz, 2H), 1.35 (t, J=7 Hz, 3H).

EXAMPLE 6 p-Tolylphenylphosphine oxide

A solution of p-tolylmagnesium bromide [prepared from p-bromotoluene(29.1 g, 0.16 mol) and magnesium (4.38 g, 0.18 g-atom)] in ether (100mL) was treated with a solution of ethyl phenylphosphonite (13,6 g, 0.08mol) in ether (50 mL) with vigorous mechanical stirring. The mixture washeated at reflux for 1/2 hr., then 100 mL of 25% sulfuric acid was addedcautiously. Three layers formed; the bottom (aqueous) layer wasextracted with toluene. Addition of NaHCO₃ to the combined upper layersproduced a vigorous reaction and a single organic phase. The organicphase was washed with water and with saturated NaCl, dried andevaporated to give an oil (14 g). Kugelrohr distillation at 120°-160° C.(0.1 mmHg) followed by chromatography on silica gel (CHCL₃), then 10%MeOH-CHCl₃) gave 7.1 g of an oil. This was distilled in the Kugelrohragain (150° C., 0.1 mmHg) to give 6.2 g of product which appears to bepure by NMR and crystallized on standing. ¹ H NMR (CDCl₃) δ8.0-7.2 (m,9H), 8.08 (d, J=480 Hz, 1H), 2.42 (s, 3H).

EXAMPLE 7 Preparation of Phosphinited Polystyrene

A previously prepared sample of brominated polystyrene beads (Bio-BeadsS-X1, 200-400 mesh) containing 17.1% bromine (27% of the rings) was usedin most of the preparations. See S. E. Jacobson, et al. JACS, (1979)101, 6938 which is hereby incorporated by reference. The polymer (3.0 g,6.4 meq Br⁻) was placed in an H-reactor and degassed. Into the other armof the reactor was syringed a three-fold excess of n-butyl lithium inhexane under a stream of argon. This was concentrated on the vacuum lineto about 3 mL, then about 20 mL of dry toluene was distilled onto thebutyl lithium and about 10 mL of toluene onto the polymer. The n-butyllithium solution was then filtered onto the polymer at -78° C., themixture warmed to room temperature and then heated in an oil bath at 60°C. for 3 hrs. The suspension was then filtered through the glass frit inthe H-reactor and part of the toluene was redistilled back onto the sideof the polymer. After filtering again, the toluene was poured off undera stream of argon, then fresh toluene was distilled into the armcontaining the polymer. The mixture was stirred briefly, then filtered,and the toluene poured out under argon. Fresh toluene (25 mL) was againdistilled onto the polymer, the mixture cooled to 0° C., then treatedvia syringe with the phosphiniting agent (2-3 equivalents), warmed toroom temperature, and stirred for one hour. The mixture was filtered andsome of the toluene distilled back onto the polymer. This was stirredbriefly and filtered again, then the toluene was poured off under argon.The polymer was then washed repeatedly with THF and with THF/isopropanol(1/1) in order to remove all traces of base, lithium chloride andunreacted phosphorus reagent. Inadequate washing of the polymer leads toformation of Michael adducts of acrylonitrile and alcohol in thedimerization runs. A typical analysis of the phosphinited polystyrenefrom a preparation using p-CH₃ OC₆ H₄ P(Cl)OEt as phosphiniting agentwas: C, 83.2; H, 7.90; P, 4.32; Br, 0.11. Calculated for completereplacement of bromine with p-CH₃ OC₆ H₄ P(OEt): C, 81.0; H, 8.09; P,5.3. A³¹ P NMR spectrum from one of the better preparations is shown inFIG. 1a. The large broad peak in the 100-120 ppm region (relative to 85%H₃ PO.sub. 4) os due to phosphinite phosphorus, by comparison to solublereference samples. The peak at -18 ppm is due to tertiary phosphine,while the two peaks in the 20-40 ppm range are due to P(V) compounds,presumably tertiary phosphine oxide (Arbuzov rearrangement product) andperhaps phosphinate or secondary phosphine oxide. The other peaks are ofunknown origin. Samples prepared using phosphonous dichlorides as thephosphiniting agent showed much larger tertiary phosphine peaks, whilethose prepared using phosphonites as the phosphorus reagent had verylarge peaks in the P(V) region.

EXAMPLE 8 Dimerization Runs

In a typical dimerization run, hexamethylbenzene, an internal standard,(800 mg, 4.93 mmol) was accurately weighted and placed in a thick-walledglass reaction vessel. To this, ca. 0.37 mmol of catalyst (monomer orpolymer) listed in Table I was added and degassed on a vacuum line.Next, the following dry reagents were distilled in on a vacuum line: 1mL of isopropanol, 3 mL of acrylonitrile, and 9 mL of toluene.Approximately 1 mL of dry cyclohexane was accurately weighted into aspecially designed vessel, then transferred on the vacuum line to thereaction vessel by means of a small U-shaped tube designed to minimizethe distillation path and thus facilitate accurate transfer of theinternal standard. The solution was then sampled under a stream of argonso that a gas chromatogram of the starting mixture could be obtained.The reaction vessel was sealed with a high vacuum stopcock and placed inan oil bath at 60° C. At varying intervals, the reactor was removed fromthe bath, cooled to room temperature, and sampled under a stream ofargon.

Gas chromatographic analyses were performed using the Porapak P columnand a temperature program starting at 60° C., increasing at 8° C./min.for 4 min., then at 32° C./min. to 240° C. and holding for 4 min.Reference standards were prepared using cyclohexane andhexamethylbenzene as internal standards. Cyclohexane was used tocalculate acrylonitrile concentration and the hexamethylbenzene was usedfor measuring the concentrations of methyleneglutaronitrile and the cis-and trans-1,4-dicyano-1-butene products.

EXAMPLE 9 Long-term Stability of Ethyl Di-p-tolylphosphinite

This experiment was run in the same way as described in Example 8, but alarger amount of all of the reactants was employed, except for thecatalyst, Tolyl₂ POEt. In this case, 30 mg of catalyst was used with 6 gof hexamethylbenzene, 6.7 mL of isopropanol, 7 mL of cyclohexane, 60 mLof toluene and 20 mL of acrylonitrile. A sample of this solution wassealed in an NMR tube under argon and heated together with the pressuretube at 60° C. At intervals the pressure tube was removed from the oilbath and sampled in the usual way. At the same time, the NMR tube wasremoved. Analysis by ³¹ P NMR showed all of the phosphorus in thepressure tube had been converted to P(V) due to repeated openings of thetube, whereas most of the phosphorus in the NMR tube had remained in theform of P(III). The results are summarized in Table II.

EXAMPLE 10 Long-term Stability of Phosphinited Polystyrene

Attempts to run the dimerization in an H-reactor using the polymericcatalyst, ethyl p-methoxyphenylphosphinated polystyrene; filtering offthe reaction solution, drying the polymer, and reusing it resulted in arapid decline in the performance of the catalysts from one run to thenext. This may be due to a number of factors, especially concentrationof the dimers and oligomers in the presence of the catalyst. To avoidthis problem, the dimerization was run in the same way as described inExample 8 with the soluble catalyst. Thus, 400 mg of phosphinitedpolystyrene was combined in a solvent reservoir with 6 g ofhexamethylbenzene, 6.7 mL of isopropanol, 7 mL of cyclohexane, 60 mL oftoluene and 20 mL of acrylonitrile, heated at 60° C. and sampled atintervals. At the end of the experiment, the polymer was recovered andanalyzed by ³¹ P NMR spectroscopy: all of the phosphorus had beenconverted to P(V). The results are summarized in Table III.

                  TABLE I                                                         ______________________________________                                        Dimerization of Acrylonitrile to 1,4-Dicyano-1-butene.sup.a                   Catalyst          Time (Hr) % Conv.  % Sel..sup.f                             ______________________________________                                        (p-Tolyl).sub.2 POi-Pr.sup.b                                                                     3        28       85                                                         21        85       75                                       Ph.sub.2 POEt.sup.b                                                                              3         9.sup.e 80.sup.e                                                   26        49       81                                                         72        81       76                                       (p-Tolyl).sub.2 POEt.sup.b                                                                       3        36       96                                                         24        89.sup.e 91                                       (p-Tolyl).sub.2 POEt.sup.b                                                                       3        25       88                                                         24        87.sup.e 99.sup.e                                  ##STR5##          3 24     23 77    68 75                                     ##STR6##          3 24     24 80    80 76                                     ##STR7##          3 24     17.sup.e 68                                                                            80.sup.e 88                               ##STR8##          3  6 12  46 65 82 89 88 85                                  ##STR9##          3        58       98                                       ______________________________________                                         Footnotes to Table I                                                          .sup.a Conditions: 800 mg of hexamethylbenzene, 1 mL of cyclohexane, 3 mL     of acrylonitrile, 9 mL of toluene, 1 mL of iPrOH, T = 60° C., P =      1.5 atm                                                                       .sup.b 100 μL.                                                             .sup.c 200 mg.                                                                .sup.d 500 mg.                                                                .sup.e Results at low or high conversion are approximate due to               uncertainty in integration of the G.C. peaks.                                 .sup.f % selectivity represents the yield of cis and                          trans1,4-dicyano-1-butene based on acrylonitrile consumed.                    *Polystyrene crosslinked with 1 wt % divinylbenzene                      

                  TABLE II                                                        ______________________________________                                        Stability of Ethyl Di-p-Tolylphosphinite.sup.a                                Time (Hrs)                                                                              % Conv.     % Selec..sup.b                                                                          % P(III)                                      ______________________________________                                         0        --          --        83                                            13        35          94        82                                            21        48          97        82                                            35        64          98        79                                            43        67          91        --                                            57        72          92        76                                            127       68          92        63                                            ______________________________________                                         .sup.a Conditions: 0.24 mmol of catalyst, of 6.0 g of hexamethylbenzene,      mL of cyclohexane, 20 mL of acrylonitrile, 6.7 mL of isopropanol, 60 mL o     toluene, 60° C. in a sealed NMR tube.                                  .sup.b Selectivity represents the yield of cis and trans                      1,4dicyano-1-butene based on acrylonitrile consumed.                     

                  TABLE III                                                       ______________________________________                                        Stability of Phosphinited Polystyrene.sup.a                                   Time (Hrs)     % Conv.  % Selec..sup.b                                        ______________________________________                                        19             20       67                                                    26             26       62                                                    44             36       62                                                    67             43       58                                                    91             47       53                                                    ______________________________________                                         .sup.a Conditions: 400 mg catalyst:                                           ##STR10##                                                                     is polystyrene crosslinked with 1 weight % divinylbenzene, 6.0 g of           hexamethylbenzene, 7 mL of cyclohexane, 20 mL of acrylonitrile, 6.7 mL of     isopropanol, 60 mL of toluene, 60° C.                                  .sup.b Selectivity represents the yield of cis and                            trans1,4-dicyano-1-butene based on acrylonitrile consumed.               

EXAMPLE 11 Acrylonitrile Dimerization using Flow Reactor

This Example was run in the apparatus illustrated in FIG. 2. A flowreactor was assembled using two 0.9×30 cm glass, water-jacketed HPLCcolumns 13, 19, a piston-type HPLC pump 11 and a reservoir 2 fitted withstopcocks 4, 5 and a side arm 3 to allow addition of reagents with theexclusion of atmospheric oxygen and moisture. The exit of the secondcolumn 19 was attached to a pressure gauge 23, a three-way stopcock 25and a graduated receiver 27. The inlet tube 26 to the receiver ¢wasattached via a side arm to a mercury bubbler (not shown) which allowedapplication of 30 cm Hg pressure to the system. At least 20 cm Hgpressure is necessary to prevent bubble formation in the reactor columns19 and dry columns 13 and 16.

The two columns were fitted with adjustable plungers and stopcocks ateach end. A three-way stopcock 17 was used at the bottom (inlet) end ofthe column 19 holding the catalyst resin. The two columns were dried at150° C., then placed while still hot in the port of a dry box. In thedry box, one column 13 was charged with 10 g of 16 mm pellets of 3Amolecular sieves which had been activated at 200° C. while beingevacuated on a vacuum line, then allowed to cool under dry argon. Thesecond column 19 was charged with 2.0 g (2.9 mmol of phosphorus) of theethyl p-methoxyphenylphosphinite polystyrene catalyst bearing previouslydescribed in Example 10. Both columns were closed and removed from thedry box, then attached to the remainder of the system. Column 16 was notused in this experiment.

The solvent reservoir was filled, under argon, with a degassed and drysolvent mixture of diisopropyl phenylphosphonite (20 μL), toluene (50mL) and isopropanol (5 mL).

The solvent mixture was pumped through the columns at a rate of 22mL/hr. until all bubbles of argon had been removed, then the watercirculating bath was turned on, the system pressurized to 30 cm Hg andthe temperature of the columns 13, 19 raised to 60° C. The catalystresin had swollen to about 13 mL volume.

In a specially designed reagent vessel 1, was placed 150μL diisopropylphenylphosphonite. The flask was attached to a vacuum line and thefollowing dry reagents distilled in: toluene (270 mL), isopropanol (27mL), cyclohexane (20.6 g, 26 mL) and acrylonitrile (67.8 g, 84 mL).

Vessel 1 was filled with argon, warmed to room temperature and thereagents thoroughly mixed. Vessel 1 was then attached to reservoir 2 viathe sidearm 8 which was repeatedly evacuated and filled with argon. Thereservoir 2 was evacuated and the contents of flask B transferred to itby opening the stopcock 9 above the filter 10. Pumping speed wasadjusted to 7.8 mL/hr and this point was designated as time 0 hr.

The effluent from the reactor was collected in 125 mL graduatedreceivers 27 which were changed periodically at intervals of 10-13 hrs.Evaporation of each of these samples at 35° C. (1 mm Hg) left an oilwhich consisted of the acrylonitrile dimers and higher oligomers. Thesamples were further analyzed by gas chromatography and by Kugelrohrdistillation of the dimers [linear and branched at 80°-100° C. (0.1 mmHg)]. Percent selectivities to dimers (see Table IV) were 90-91% amixture of dimers (92% linear vs 8% branched dimers).

At intervals, samples of the reaction mixture were taken using thethree-way stopcocks 17 and 25 before and after the catalyst bed. Gaschromatographic analysis of the amount of acrylonitrile present relativeto cyclohexane allowed calculation of the percent conversion. Thepercent conversion slowly declined during the experiment from 63%initially to 40% at 184 hours (see FIG. 2).

Additional batches of the reagent mixture were prepared and transferredto the reservoir when needed. Percent conversions were measured forperiods when the flow rate was 7.7±0.1 mL/hr.

At 184 hours the last reservoir of reagents had been consumed and amixture of toluene:isopropanol (10:1) was added to purge all of theremaining reagents through the system. The combined collected fractionscontained 109.64 gm of products, equivalent to 2.066 moles ofacrylonitrile converted. This represents 714 catalyst turnovers. Resultsare summarized in Table IV and FIG. 3.

After about 30 hours of reaction, the pump had to be disconnected and avalve was changed. After replacement of the valve and reconnection ofthe pump, the reaction was continued but the percent conversion startedto decline faster. It is believed that this interruption causedcontamination of the catalyst by moisture and oxygen. It is furtherbelieved that if this interruption had not occurred and if the reagentmixture had been more effectively dried such as by use ofpolystyrene-bound dialkylphosphonite (e.g., placed in column 16 as shownin FIG. 2), the decline in the activity of the catalyst as measured bythe percent conversion would have been lower.

                  TABLE IV                                                        ______________________________________                                        Acrylonitrile Dimerization Products                                                  Vol.     Wt     (residue).sup.a                                                                       (dimers).sup.b                                                                       % Selec..sup.c,d                        Receiver                                                                             mL       g      Wt. g   Wt. g  to dimers                               ______________________________________                                        1      103      88.9   9.76    8.87   91                                      2      98.5     86.2   10.91                                                  3      84.5     73.2   9.14                                                   4      84       72.5   8.09    7.33   91                                      5      80       68.7   7.11                                                   6      73       62.8   6.62                                                   7      77.5     67.5   7.01    6.31   90                                      8      80       68.6   6.86                                                   9      98       84.7   7.79                                                   10     80       67.5   6.01    5.45   91                                      11     91       78.2   6.82                                                   12     73       62.6   5.32                                                   13     94       80.3   5.22    5.57   90                                      14     94       80.4   5.97                                                   15     120             4.92                                                   Combined samples                                                                             1.09                                                           Total          109.64                                                         ______________________________________                                         .sup.a After evaporation of reagents at 35° C. (1 mm Hg)               .sup.b Isolated by Kugelrohr distillation at 80-100° C. (0.1 mm        Hg).                                                                          .sup.c 92% 1,4dicyano-1-butenes, 8% methyleneglutaronitrile.                  .sup.d % Selectivity to DCB1 = % Selec. to dimers × 92% (% DCB1 in      dimers).                                                                 

EXAMPLE 12 Preparation of the polystyrene-bound phosphonous dichloride○p -C₆ H₄ -PCl₂

In a typical preparation, 1 gm (9.6 mmol) polystyrene resin cross-linkedwith 1 weight % divinylbenzene (Bio Beads. S-X1, 200-400 mesh) and 1.33gm (100 mmol) anhydrous aluminum chloride (AlCl₃) were placed under aninert atmosphere into one side of an "H"-reactor, as described inExample 7, and equipped with a reflux condenser with an argon inlet;12.5 mL (excess) of degassed PCl₃ were syringed, under a stream ofargon, into the reactor which was then placed in an oil bath at 60° C.and stirred for 3 hours. The reaction mixture was degassed and filteredthrough the coarse glass frit and the filtrate poured off under argon.The polymer product was washed extensively with dry THF to removeresidual AlCl₃ and dried in vacuo; yield 1.7 gm, ³¹ P NMR (swollen inCH₂ Cl₂) δ162 ppm (phosphonous dichloride). Phosphorus, 13.0% by weight,was incorporated into polymer indicating that ca. 75% of the rings werefunctionalized.

EXAMPLE 13 Preparation of the polystyrene-bound diisopropyl phosphonite

One gram (4.9 mmol) of the phosphonous dichloride was charged under aninert atmosphere into an "H"-reactor which was then evacuated on thevacuum line. Fifteen mL of dry pyridine were distilled onto the polymerand 1.2 mL (147 mmol) of dry isopropanol were distilled into theopposite leg of the reactor. The polymer suspension was stirred at 0° C.for 1 hour while the isopropanol slowly distilled over. The mixture waswarmed to room temperature and stirred an additional hour. The reactionwas filtered through a glass frit, and the the filtrate was poured offunder argon. The polymer was washed repeatedly with dry methylenechloride and dried in vacuo. The ³¹ P NMR spectrum contained a peak at162 ppm (broad peak) indicative of phosphonite phosphorus.

EXAMPLE 14

This example illustrates the use of polystyrene-bound diisopropylphosphonite of Example 13 as a drying agent in acrylonitriledimerization using the flow reactor of Example 11. A water-jacketed HPLCcolumn 16 is placed in line 15 after column 13 and before the catalystcolumn 19 of FIG. 2. The procedure of Example 11 is followed. A lowerdecline in the % conversion after a longer reaction time is expected dueto a more complete removal of water.

EXAMPLE 15 Preparation of polystyrene-bound 3,4,5-trimethylphenylphosphinous chloride.

One gram (4.9 mmol) of the Polystyrene-bound phosphonous dichloride and0.72 gm (5.4 mmol) of AlCl₃ were charged under an inert atmosphere intoan H-reactor equipped with a reflux condenser with an argon inlet.Fifteen mL (excess) of 1,2,3-trimethylbenzene were syringed in under astream of argon and suspension was stirred at 60° C. for 6 hours. Thefiltrate was poured off under argon, and the polymer was washed with dryTHF, then with THF/pyridine in the ratio of 15/2 and dried in vacuo. The³¹ P NMR spectrum contained a peak at 85 ppm (phosphinous chloridephosphorus), and a smaller peak due to dichloride at 162 ppm. In anotherexperiment, the H-reactor was charged as described above and thesuspension was stirred under a stream of argon at 100° C. for 1 h. Thepolymer was washed and dried as described above. The ³¹ P NMR spectrumindicated that ca. 95% of the phosphorus was in the form of phosphinouschloride (peak at 85 ppm) and that only ca. 5% of unreacted startingmaterial was present (peak at 162 ppm).

EXAMPLE 16 Preparation of the polystyrene-bound isopropyl3,4,5-trimethylphenyl phosphinite

One gram of the phosphinous chloride prepared as described in Example 15was charged into an H-reactor under an inert atmosphere and evacuated onthe vacuum line. 15 mL of dry THF and 0.5 mL of dry pyridine weredistilled onto the polymer and 0.5 mL (6.1 mmol) of dry isopropanol wasdistilled into the opposite leg. The reaction conditions of Example 13were followed. The polymer was washed extensively with dry THF. The ³¹ PNMR spectrum contained a peak at 107 ppm indicative of phosphinitephosphorus (ca. 90% of P) and a smaller peak at 44 ppm (ca. 10% of P)due to an unidentified impurity. See FIG. 1b.

EXAMPLE 17a Reaction 3,4,5-(CH₃)₃ C₆ H₂ PCl₂ and Polystyrene at 60° C.

One gram (9.6 mmol) of polystyrene resin cross-linked with 1%divinylbenzene (Bio Beads, S-X1, 200-400 mesh) and 1.33 gm (10.0 mmol)AlCl₃ were charged under an inert atmosphere into an H-reactor equippedwith a reflux condenser and argon inlet. The polymer was swollen in 10mL of dry 1,1,2,2-tetrachloroethane which was added (syringe) underargon. 3,4,5-(CH₃)₃ C₆ H₂ PCl₂ (2.8 gm, 12.7 mmol) dissolved in 2 mL dry1,1,2,2-tetrachloroethane was added to reaction mixture via syringeunder argon and the reaction mixture so formed was heated at 60° C. for4 hours. The suspension was degassed and filtered through the glassfrit, and the filtrate poured off under argon. The polymer was washedextensively with dry THF. The ³¹ P NMR spectrum showed no incorporationof phosphorus into the polymer.

EXAMPLE 17b Reaction of 3,4,5-(CH₃)₃ -C₆ H₂ PCl₂ with Polystyrene at100° C.

The reaction described in Example 17a was repeated excepting that thereaction mixture so formed was heated at 100° C. for 2 hours. The darkbrown reaction mixture produced was filtered under argon and a red brownsolid recovered and washed three times with 15 mL portions of THF. Theyellow-orange solid was washed with dry CH₂ Cl₂, again with THF (thecolor of solid remained unchanged) and dried in vacuo to give a gummyyellow-orange solid. The ³¹ P NMR analysis on the gummy solid swollen inCH₂ Cl₂ gave a spectrum consisting of a large broad multiplet ofunassigned peaks at 70 ppm, 51.4 ppm, 46 ppm and 36 ppm, said unassignedpeaks indicative of incorporation of phosphorus into polymer and a smallpeak at 162 ppm; indicative of a phosphonous dichloride. There was nopeak at 85 ppm indicative of uncomplexed polymer-bound phosphinouschloride.

EXAMPLE 17c Attempted Preparation of Poly-styrene-bound Isopropyl3,4,5-trimethylphenyl phosphinite

The reaction product of Example 17b was treated in accordance with theapparatus and procedure of Example 16. Dry THF and pyridine weredistilled into ca. 700 mg of the gummy yellow-orange solid of Example17b and removed by filtration. Fresh dry THF (12 mL) dry pyridine (2 mL)and dry isopropanol (2.0 mL) were distilled onto polymer. The reactionconditions and apparatus of Example 13 were then used excepting that thereaction product was washed with THF and a THF-isopropanol mixture anddried in vacuo. There was recovered 0.53 g of a yellow-orange gummysolid. The ³¹ P NMR spectrum contained a broad multiplet of peakscentered around 30 ppm indicative of phosphorus (V). The phosphorussignal was very weak, indicating little phosphorus was incorporated andthe spectrum contained no peak around 110 ppm indicating no phosphinitephosphorus was present.

EXAMPLE 18 Trimethylsilyl dibutylphosphinite

The procedure described in Tetrahedron, 1967, 23, 1065 (M. Grayson etal.) was followed. Dibutylphosphine oxide, prepared from butyl magnesiumbromide and diethylphosphite, (3.3 g, 20 mmol) and triethylamine (2.02g, 20 mml) were dissolved in toluene (20 mL) and treated with a solutionof trimethylsilyl chloride (2.17 g, 20 mmol) in toluene (5 mL) at roomtemperature. The solution got very warm and a precipitate formedimmediately. The mixture was heated at 80° C. for two hours, thenfiltered, washed with toluene, and concentrated. Kugelrohr distillationat 80° C. (1.5 mmHg) afforded 4.1 g (86%) of the desired product. ¹ HNMR (CDCl₃) δ1.8-1.2 (m, 6H), 1.1-0.7 (m, 3H), 0.17 (s, 9H).

EXAMPLE 19 Attempted Dimerization of ACN using TrimethylsilylDibutylphosphinite

A dimerization reaction mixture was prepared in accordance with theapparatus and procedure of Example 8 from cyclohexane (1 mL),isopropanol (1 mL), acrylonitrile (3 mL), toluene (9 mL),hexamethylbenzene (1.334 g ) and trimethylsilyl dibutylphosphonite (0.1mL) of Example 18. The solution was heated at 60° C. for 18 hrs, thensampled under argon. GC analysis showed no reaction products and noconversion of the acrylonitrile. Analysis of the reaction mixture by ³¹P NMR showed one major peak at δ46 ppm, corresponding to a rearrangementproduct, and nothing at 117 ppm relative to 85% H₃ po₄ where thestarting phosphinite phosphorus appears.

EXAMPLE 20 4-(2-Hydroxypropyl)polystyrene

A 3.0 g sample of brominated polystyrene containing 29% bromine andcrosslinked with 1% of divinylbenzene was placed on one side of anH-reactor. Butyl lithium (20 mL, 2.4M) was syringed into the other side,the hexane solvent was mostly evaporated and replaced by 30 mL drytoluene. The toluene solution was filtered onto the polymer and themixture was heated at 60° C. for 3 h. The polymer was filtered, thetoluene poured off and fresh toluene distilled in. After severalwashings the toluene was poured off and the polymer dried. Fresh toluene(30 mL) was then distilled onto the polymer followed by 1.1 mL ofpropylene oxide (15.7 mmol). The mixture was stirred at room temperaturefor 20 h., then filtered, the solvent poured off and 20 mL ofisopropanol were distilled in. After stirring, the polymer was filteredagain and then washed in the air with isopropanol (2× 100 mL),isopropanol containing several drops of concentrated hydrochloric acid(2×100 mL) and again with isopropanol (2×100 mL). Drying overnight in avacuum oven at 60° C. gave 2.5 g of product. Analysis for hydroxylcontent gave a value of 3.7 meq OH/g of polymer.

EXAMPLES 21-22 Partially Phosphinited Hydroxypropylpolystyrene

A 1.0 g sample of the hydroxypropylpolystyrene prepared as described inExample 20 was treated in an H-reactor with di-p-tolylphosphinouschloride (0.37 g, 1.49 mmol) in pyridine (15 mL). After 3 days themixture was filtered, washed with pyridine once and with dichloromethaneseveral times. The dried polymer weighed 0.95 g. Phosphorus NMR Spectrumcontained only a single broad peak at ca. δ107 ppm. Fully phosphinitedhydroxypropylpolystyrene was prepared similarly using an excess ofphosphinous chloride. The ³¹ P NMR spectrum contained only a singlebroad peak at ca. δ107 ppm.

EXAMPLE 23 Partial Phosphination of TDI-Cross-linked PVAL

A sample of polyvinyl alcohol cross-linked with about 5%tolylenediisocyanate was dried in vacuo at 60° C. The polymer (0.33 g)was placed in an H-reactor and treated with diphenylphosphinous chloride(0.50 g, 2.25 mmol) in pyridine (15 mL) for 4 days at room temperature.After filtration, the polymer was washed several times withdichloromethane and dried. Yield: 0.23 g. Phosphorus NMR showed asubstantial amount of phosphorus incorporation, with about 90% in thephosphinite form. The sample was recovered from the NMR tube, dried andused in a dimerization run (See Example 28) but no conversion of ACN wasobserved. (See Table V).

EXAMPLE 24 Complete Phosphination of TDI-Cross-linked PVAL

A 0.5 g sample of dried, 5% TDI-cross-linked, 80% hydrolyzed polyvinylacetate was treated with a slight excess of di-p-tolylphosphinouschloride (2.0 g, 8 mmol) in pyridine (15 mL) for 4 days at roomtemperature. The polymer was filtered, washed with dichloromethane anddried. Yield: 0.49 g. The phosphorus NMR spectrum showed a strong peakin the region (δ110 ppm) expected for phosphinite and a smaller peak inthe P(V) region. Thus, although there was no weight gain, the recoveredmaterial contained an appreciable amount of phosphorus. This polymer wasused in a dimerization reaction with neopentyl alcohol. (See Example28). No conversion of ACN was indicated by GLC.

EXAMPLE 25 Fully Phosphinited TOYOPEARL®

A 1.0 g of dried, coarse TOYOPEARL® was treated with excessdi-p-tolylphosphinous chloride (2.5 g, 10 mmol) in pyridine (20 mL) inan H-reactor. After 2 days at room temperature the reaction was stopped.The mixture could not be filtered, so the pyridine was pumped off anddichloromethane distilled in. The polymer was stirred briefly, thenfiltered. After several more washings with dichloromethane, the productwas dried on the vacuum line. An appreciable amount of material was lostdue to the fine particles being pulled up into the vacuum line. Yield:1.45 g. The ³¹ P NMR spectrum showed a strong broad peak at δ115 ppmphosphinite phosphorus and a number of sharp resonances of lowerintensities due to monomeric phosphorus species.

EXAMPLE 26 Partially Phosphinited TOYOPEARL® (30%)

Superfine TOYOPEARL® (3.0 g) was treated with about 0.3 equivalents ofdi-p-tolylphosphinous chloride (1.4 g) in pyridine for 2 days at roomtemperature. The product was filtered in a glove bag and washed withdichloromethane, then dried overnight in a vacuum oven. It was thenwashed repeatedly with dichloromethane in an H-reactor and redried.Yield: 2.7 g. Phosphorus NMR shows a broad peak in the phosphiniteregion and a smaller broad peak in the P(V) region.

EXAMPLE 27 Partially Phosphinited TOYOPEARL® (6%)

A 4.0 g sample of coarse TOYOPEARL® was treated with about 0.06equivalents of di-p-tolylphosphinous chloride (0.44 g, 1.77 mmol) inpyridine (30 mL). The mixture was stirred overnight at room temperature,filtered under argon and washed with dichloromethane, then dried on thevacuum line. Yield: 4.35 g. The phosphorus NMR showed a single broadresonance at δ115 ppm (due to phosphinite phosphorus) and a small amountof a monomeric P(V) compound.

COMPARATIVE EXAMPLE 28

Dimerizations of acrylonitrile using hydroxyl-containing polymer-boundphosphinites of Examples 21-27 were run in accordance with the procedureof Example 8 excepting that no isopropanol was added. In runs 6-7wherein all the OH groups of polymer-bound catalyst were converted intophosphinite at the start of the reaction, neopentyl alcohol was added.See Table V for a summary of results.

ACN Dimerization Runs 6-8 of Example 28 Dimerization using FullyPhosphinited Toyopearl and Neopentyl Alcohol

A dimerization reaction was carried out in accordance with the procedureand apparatus of Example 8 using the fully phosphinited TOYOPEARL ofExample 25 as the catalyst and neopentyl alcohol as the added alcohol.After 20 h, the reaction mixture was analyzed. Conversion was 90% andselectivity to 1,4-dicyano-1-butenes also about 90%. The reactionmixture was filtered, concentrated and the phosphorus NMR Spectrum wasobtained on a methylene chloride solution of the residue. The ³¹ P NMRspectrum showed several peaks, the major ones being at δ112 ppm, due toneopentyl di-p-tolylphosphinite, and a δ29 ppm, probably due to thetertiary phosphine oxide. The ³¹ P NMR spectrum of the recovered polymershowed no polymer-bound phosphorus. Repetition of the experiment gave14% conversion after 3 h, with >90% selectivity; in addition to thepeaks noted above, the ³¹ P NMR showed a smaller peak at δ-50 ppm due tothe pentacoordinate phosphorane.

                  TABLE V                                                         ______________________________________                                        ACN Dimerization Runs Using Various                                           Polymer-Bound Phosphinite Without Added Alcohol.sup.a                         Polymer.sup.b                                                                              % P.sup.c                                                                            Time (Hr.)                                                                              Results                                         ______________________________________                                        1   PS--OP--Tolyl.sub.2.sup.1                                                                   40    22.5    No ACN conversion                             2   PS--OP--Tolyl.sub.2.sup.1                                                                   40    5       Mainly P(V)                                   3   PS--OP--Tolyl.sub.2.sup.1                                                                   5     24      No ACN conversion                             4   TDI--PVAL.sup.3                                                                             40    6       No ACN conversion                             5   TDI--PVAL.sup.4                                                                            100    24      No ACN conversion                             6   TOYOPEARL ®.sup.5                                                                      100.sup.d                                                                            20      90% conversion;                                                               90% selectivity                                                               to DCB-1; No                                                                  polymer-bound                                                                 phosphorus after                                                              20 hrs; neopentyl                                                             di-p-tolylphos-                                                               phinite present                               7   TOYOPEARL ®.sup.5                                                                      100.sup.d                                                                            3       14% conversion;                                                               90% Selectivity                                                               to DCB-1; No                                                                  polymer-bound                                                                 phosphorus after                                                              3 hrs; neopentyl                                                              di-p-tolyl-                                                                   phosphonite and                                                               P(V) present                                  8   TOYOPEARL ®.sup.6                                                                       6     24      11% conversion;                                                               37% selectivity                                                               to DCB-1                                      ______________________________________                                         .sup.a 60° C. Typical amounts: 9 mL of toluene, 3 mL of ACN, 1 mL      of cyclohexane, 0.2 mmol of phosphorus.                                       .sup.b PS--O = 4(2'-hydroxy-1'-propylpolystyrene crosslinked with 1% of       divinylbenzene. (See Examples 21-22); TDI--PVAL = 5% Tolylene diisocyanat     crosslinked polyvinyl alcohol.                                                .sup.c Percent of polymerbound OH groups derivatized with P--(pCH.sub.3       C.sub.6 H.sub.5).sub.2 groups.                                                .sup.d Neopentyl alcohol was added.                                           Preparation of Polymers listed in Table V                                     1. See Examples 21, 22.                                                       2. See Examples 21, 22.                                                       3. See Examples 23.                                                           4. See Examples 24.                                                           5. See Examples 25.                                                           6. See Examples 27.                                                      

We claim:
 1. A heterogeneous catalytic process for convertingacrylonitrile into 1,4-dicyano-1-butane which comprises contacting aliquid phase comprising acrylonitrile with an effective amount of aninsoluble solid polystyrene bound diarylphosphinite catalyst for timesufficient to effect conversion of acrylonitrile into1,4-dicyano-1-butene, wherein said catalyst has the formula: ##STR11##wherein: ○p represents polystyrene;--C₆ H₄ -- represents phenylene ringsderived from at least about 5% of the pendant phenyl groups of saidpolystyrene; --R represents an alkyl straight chain or branched havingfrom 1 to 10 carbons, or cycloalkyl having from about 5 to 10 carbons;--Ar represents an aryl group having the formula ##STR12## wherein R_(a)through R_(e) are independently selected from the group consisting of(a) hydrogen; (b) alkyl, straight chain or branched, having 1 to 10carbons; (c) cycloalkyl having from about 5 to 10 carbons; (d) --OR³wherein R³ represents alkyl having 1 to 10 carbons or cycloalkyl havingfrom 5 to 10 carbons; and (e) --N(R⁴ R⁵) wherein R⁴ and R⁵ areindependently alkyl, straight chain or branched, having 1 to 10 carbonsor cycloalkyl having from about 5 to 10 carbons;wherein two of saidR_(a) through R_(e) groups may form part of a fused alicyclic ring.
 2. Aprocess according to claim 1 wherein said moiety of the formula --C₆ H₄-- is derived from at least about 25-100% of the pendant phenyl groupsof said polystyrene.
 3. A process according to claim 2 wherein saidmoiety of the formula --C₆ H₄ -- is derived from at least about 80% ormore of the pendant phenyl groups of said polystyrene.